Movement (e.g., flexion and extension) of the natural human knee involves movements of the femur and the tibia. Specifically, during flexion and extension, the distal end of the femur and the proximal end of the tibia articulate relative to one another through a series of complex movements. Damage (e.g., trauma) or disease can deteriorate the bones, articular cartilage, and ligaments of the knee, which can ultimately affect the ability of the natural knee to function in such a manner. As a result, knee prostheses have been developed and implanted into surgically prepared ends of the femur and tibia.
One type of knee prosthesis is a mobile bearing knee that mimics the condylar and bearing surfaces of the knee to emulate the natural movement of the knee during flexion and extension. The tibial component of a mobile bearing knee prosthesis is configured to allow rotation about the central axis of the tibia. Moreover, certain types of mobile bearing knees, commonly referred to as posterior stabilized mobile bearing knees, include a tibial component having an upwardly projecting (i.e., superiorly projecting subsequent to implantation) spine that is positioned between the condyles of the femoral component. The spine is engaged by cam surfaces at the anterior and posterior ends of the femoral component to limit the relative anterior-posterior movement between the femur and the tibia.